1. Field of the Invention
The invention relates to devices and methods for securing packer elements to a packer mandrel In particular aspects, the invention relates to the use of swellable support rings as a back-up system to prevent or limit extrusion of a swellable packer element after setting.
2. Description of the Related Art
Packers are devices that are used to create a fluid seal within a wellbore. A packer typically includes a central mandrel and an expandable packer element that is carried by the packer mandrel.
U.S. Pat. No. 3,490,525 issued to Nettles describes a blow-out preventer packer unit having an elastomeric element that is molded at its ends to a pair of spaced rigid disks. During unitary molded construction of the packer unit, lips of the elastomeric sleeve are molded over a portion of the disk faces in order to strengthen the bond. Fluid elastomeric material is injected during the molding process.
U.S. Pat. No. 5,092,400 issued to Jagert describes a coiled tubing hanger device wherein a flexible packing element is bonded to upper and lower shoes by means of a mold injection bonding process.
U.S. Pat. No. 6,581,682 issued to Parent et al. describes an expandable borehole packer which incorporates granules of expandable bentonite as well as a method of pre-making the packer for later incorporation onto a pipe. Binding clamp rings are used to secure a pair of sleeves encapsulating the bentonite granules onto a pipe.
U.S. Pat. No. 5,078,211 issued to Swineford describes a plastic packer used for water wells that is typically molded out of polyurethane.
U.S. Pat. No. 7,124,831 issued to Turley et al. describes a non-metallic sealing element for use in bridge plugs, frac plugs and packers. The packer element may be made up of a polymeric composite material that is wound onto a tool mandrel and then cured in place.